Seven Steps to Healthier Trees
Most people plant trees, work hard to get them established and walk away. Trees are living organisms and we tend to think about them based on what we see above ground but the below ground structures are generally ignored. An increase in erratic weather and the possibility of high winds during storms can often time cause trees to fall.
It is a tree owner’s duty to take the responsibility to ensure a reasonable degree of safety for people or property near trees. In our area, they should be inspected twice a year to avoid an accident.
Trees often die from a series of linked events. They can transition from vigorous to stressed to injured to declining and finally to death. This is known as the mortality spiral. Mature trees that are predisposed to construction injury, excessive irrigation, excessive pruning or poor drainage will negatively affect a tree’s health due to the disruption of nutrient flow in the root system. This lack of nutrient uptake stresses the tree, and if left unchecked could result in insect and disease infestation, girdling roots, or death.
There is a seven-step process that we can do as homeowners to keep our trees healthy and safe.
The first step is to look up at the canopy. Look for the three “D’s” dead, diseased and dying. These limbs are likely to fail during storms. You may have to grab some binoculars to get a better view. Look for conchs, mushrooms, frass or sawdust. If there is dieback in the canopy the tree is beyond being stressed.
The second step is to be sure the tree does not have a lean in a particular direction. If there are any exposed roots or mounded soil near the base, it is time to take action. Inspect the trunk and branches and examine the root flare. Look for buttressing roots, cavities, and other potential failures.
Step three is to avoid buying trees that have co-dominant leaders. This is when several branches arise from the same point on the trunk. Bradford pears tend to grow this way and is often why you see them snapped in half after heavy winds. This is a problem because each limb is expanding in girth waiting to collapse. The best solution is to avoid trees growing this way. When they reach this point there is no cure.
It is important to identify the tree that you are dealing with, in regard to species and cultivar. Trees vary in their ability to compartmentalize decay. Trees such as maples and crape myrtles seal off injury very rapidly. Bradford pear is an example of a tree that does not.
The fourth step is to look for branch unions. Large branches should be half the diameter of the trunk in order for the branch collar and the branch protection zone to develop.
The fifth step is to look for trunk or branch cracks as these may lead to failure. These cracks would need to be evaluated.
The sixth step is to look for cavities, cankers, mushrooms or conchs at the base of the trunk. These can be a sign of decay in the wood. Be sure when pruning you make a clean cut and do not leave stubs behind. Trees that have cavities or gaping holes in the trunk will need to be inspected more often. In the old days, cavities were filled with concrete in hopes that this would strengthen the trunk. We now know that this actually causes more injury to the tree. Additional injury occurs when the tree continues to move normally in the wind against the stiff concrete column inside. This abrasion allows decay to move into the living wood by injuring the barrier zone formed by the tree to retard the further advance of decay. Never use concrete in trees.
Lastly, take a look at the root and root collar. A tree’s root collar is the area where the roots join the main stem or trunk. This area will have a flare leading to the major roots. The root collar is part of the tree’s trunk. Look for soil mounding, cracking near the root collar or broken roots sticking out of the soil. Also be sure that the roots are not girdling the tree. Sometimes these roots can be chiseled out but it depends on the integrity of the roots and their importance to the entire root system. Be sure to keep the soil away from the root flare and keep an eye out for conchs or mushrooms growing at the base of the tree as these can compromise the root system.
Conduct biannual tree inspections. Walk around the entire tree and look for regions that do not look normal. Look for signs and symptoms of defects. Record and document observations. Do not remove large branches or trunk sections on your own. Consult a certified arborist for advice or mitigation. To learn more about trees go to the Trees are Good website.
“It has been said that 80% of all landscape tree problems start below the ground.” Unknown Author